[Xen-changelog] [qemu-xen stable-4.10] qcow2: Fix unaligned preallocated truncation

[patchbot@xxxxxxx]

commit a25aca75f83895fd16bef572bbf31e33620b600d
Author:     Max Reitz <mreitz@xxxxxxxxxx>
AuthorDate: Mon Oct 9 23:55:31 2017 +0200
Commit:     Michael Roth <mdroth@xxxxxxxxxxxxxxxxxx>
CommitDate: Tue Dec 5 19:40:33 2017 -0600

    qcow2: Fix unaligned preallocated truncation
    
    A qcow2 image file's length is not required to have a length that is a
    multiple of the cluster size.  However, qcow2_refcount_area() expects an
    aligned value for its @start_offset parameter, so we need to round
    @old_file_size up to the next cluster boundary.
    
    Reported-by: Ping Li <pingl@xxxxxxxxxx>
    Bug: https://bugzilla.redhat.com/show_bug.cgi?id=1414049
    Signed-off-by: Max Reitz <mreitz@xxxxxxxxxx>
    Message-id: 20171009215533.12530-2-mreitz@xxxxxxxxxx
    Cc: qemu-stable@xxxxxxxxxx
    Reviewed-by: Eric Blake <eblake@xxxxxxxxxx>
    Reviewed-by: Jeff Cody <jcody@xxxxxxxxxx>
    Reviewed-by: Stefan Hajnoczi <stefanha@xxxxxxxxxx>
    Signed-off-by: Max Reitz <mreitz@xxxxxxxxxx>
    (cherry picked from commit e400ad1e1f0127b4fdabcb1c8de1e99be91788df)
    Signed-off-by: Michael Roth <mdroth@xxxxxxxxxxxxxxxxxx>
---
 block/qcow2.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/block/qcow2.c b/block/qcow2.c
index a756bf9..10e3807 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -3161,6 +3161,7 @@ static int qcow2_truncate(BlockDriverState *bs, int64_t 
offset,
                              "Failed to inquire current file length");
             return ret;
         }
+        old_file_size = ROUND_UP(old_file_size, s->cluster_size);
 
         nb_new_data_clusters = DIV_ROUND_UP(offset - old_length,
                                             s->cluster_size);
--
generated by git-patchbot for /home/xen/git/qemu-xen.git#stable-4.10

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